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03-06-2008, 09:00 PM   #1
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M & K Series Lens on K10D or K20D

Hullo Folks!

Can someone here in the know please tell me the plus and minus points of using a M and K series lens on a K10D? Specifically:

1. If aperture is set manually, does one end up always shooting in 'stopped down mode'? (Metering and focussing through a darkened viewfinde?)

2. How does image quality compare with A and F series optics?

3. Are there any metering issues?

I am specificlly looking for answers to above Qs with respect to the following M or K series lenses - 85mm/f2, 135mm/2.5, 200mm/f2.5. (Plan to buy and use them on a K20D if feasible/worthwhile.)

Lastly, what is the difference in the image quality of a 200mm/f2.5 and the FA*200mm/f2.8 ED?

Thank you all in advance for your inputs.

khukri.

03-06-2008, 09:35 PM   #2
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1. no, the lens will stop down when the shutter is pressed
2. depends on the lens, some of them are classics, and if you want true metal construction, the A and F series unless * don't cut it
3. yes people have reported issues with random underexposure

QuoteOriginally posted by Khukri Quote
Hullo Folks!

Can someone here in the know please tell me the plus and minus points of using a M and K series lens on a K10D? Specifically:

1. If aperture is set manually, does one end up always shooting in 'stopped down mode'? (Metering and focussing through a darkened viewfinde?)

2. How does image quality compare with A and F series optics?

3. Are there any metering issues?

I am specificlly looking for answers to above Qs with respect to the following M or K series lenses - 85mm/f2, 135mm/2.5, 200mm/f2.5. (Plan to buy and use them on a K20D if feasible/worthwhile.)

Lastly, what is the difference in the image quality of a 200mm/f2.5 and the FA*200mm/f2.8 ED?

Thank you all in advance for your inputs.

khukri.
03-06-2008, 11:07 PM   #3
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Hi Khukri,

1. Yes, with M and K lenses the camera will automatically stop the lens down when the shutter is pressed. With M42 lenses, then need to have a stop down switch on the lens, and manually set the aperture before you shoot.

2. I can not comment with regard to A or F lenses, but the M lenses I use are better then the kit lens. The M 50 1.4 is a beautiful sharp lens.

3. Metering with the M lenses drives me nuts. It does not work well with the K10D. Note, I do not have problems with my K100D. The metering issue does follow a pattern. With my 50mm, wide open it under exposes, mid aperature is acurate, stoped down it over exposes. All of my M lenses follow a similar pattern. I use the Histogram and I bracket my shots to compensate. It drives me nuts. Some people have reported the problem fixed by changing their focusing screen. But, the jurry is still out on that fix. There are some threads on this topic that I am following closely. I might resort to Voodoo and black magic.

Overall I am very impressed with the K10D. I really enjoy being able to use the older lenes. I just wish there was a fix for this metering issue. Pentax sells the K10D highlighting the backwards compatability of the older lenses. In my opinion, these lenses should allow acuraute metering (unlike my spelling )

Eric
03-07-2008, 06:03 AM   #4
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QuoteOriginally posted by Khukri Quote
Hullo Folks!

Can someone here in the know please tell me the plus and minus points of using a M and K series lens on a K10D? Specifically:

1. If aperture is set manually, does one end up always shooting in 'stopped down mode'? (Metering and focussing through a darkened viewfinde?)
K mount lenses - the only mode that the lens will stop down in while shooting is the M mode. in Av mode the lens will remain wide open and shot taken at maximum apature but metered for it.
M42 lenses- as others have suggested set the lens in manual and it will stop down as you turn the apature ring, this will let the calera shoot in Av mode at the apature selected but the view finder darkens as you stop down

QuoteQuote:
2. How does image quality compare with A and F series optics?
I find the image quality of the lenses I have is exceptional, I have SMC 50mm f1.4, SMC-M 100mm F4 macro, SMC 105mm F2.8, SMC 135mm F2.5, SMC 300mm F4.

Lenses can sometimes produce chromatic aberations in the out of focus areas, (Note none are APO/Ed/what ever) and some can cause internal reflections off the sensor to the back element (see another post with green spot in images) that are due to lack od Digital specific coatings, but so will A , F and early FA lenses.
QuoteQuote:
3. Are there any metering issues?
Tons with K10D, and this seems to be any lens regardless of make, even new digital lenses when used in non AE mode. My testing has given me the following impression.

at F1.4 lenses will under expose by 1 stop.

By F5.6 this has gone to over exposure by 1 stop with 1.5-2 stops over exposure by f8-f11 falling back to about +1.5 stops at f22-f32

This relation seems to hold true even for my brand new Tamron 28-75 F2.8 if I take it out of AE mode.

I can't comment on K20 as I don't own one. I have heard reports that if you use manual only lenses, using the *istD screen fixes all exposure problems with M lenses, but upsets the AE mode.

My own opinion of this is there is a problem with light reflections off the focusing screen (where metering is also taken) that changes as a function of maximum apature. the curve I mention above is programmed into the camera so that in AE mode the camera sorts it all out, but in Manual exposure or manual apature lenses, since the body does not know the maximum apature it can't do this. I have requested that pentax allow entry of lens max/min apature and control the apature from the camera, which would solve this problem as well as allow for P-TTL flash. but so far no answer.
QuoteQuote:
I am specificlly looking for answers to above Qs with respect to the following M or K series lenses - 85mm/f2, 135mm/2.5, 200mm/f2.5. (Plan to buy and use them on a K20D if feasible/worthwhile.)
You should add an F1.4 50mm also to this list, and if you can find it, sub the K mount 85 F1.8 as opposed to the M 85 F2. but you will have a lot of competition there as I am still looking for an 85 also. 135F2.5 as long as it is the SMC and not Takumar is a great lens, cant comment on the 200 F2.5 as it is also on the wish list.
QuoteQuote:
Lastly, what is the difference in the image quality of a 200mm/f2.5 and the FA*200mm/f2.8 ED?

Thank you all in advance for your inputs.

khukri.
Cant comment obviously on any of the 200's sorry

Hope this helps

03-07-2008, 10:05 PM   #5
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Dear k100d, Eric and Lowell,

Thank you so much for your inputs; I do appreciate the time you took to write this, Lowell!

So, if you happen to come across a spare 85mm/1.8 (after you have got one for yourelf!), Lowell, do give me a holler! My email is <khukri@hotmail.com>

I generally do not use normal 50mm optics, except occasionally the 50 macro. I am into either very wide (<28mm) or very telephoto (>200mm) landscapes/nature.

I also note that all of you are from Canada. And I am looking for Pentax stuff from Canada to be purchased within the next month. Incase you or any of your friends or retai outlest syou know are disposing accessories that can be used on a K20D let me know. Stuff like angle finder, viewfinder magnifier and yes, a 50mm/2.8 macro.

Before I end may I wish a slight clarification, please:

Lowell, you say that, "K mount lenses - .... in Av mode the lens will remain wide open and shot taken at maximum apature but metered for it."

k100d, you say that, "no, the lens will stop down when the shutter is pressed"

And Eric, says, "Yes, with M and K lenses the camera will automatically stop the lens down when the shutter is pressed."

From above quote of Lowell, I understand that the K lens will work only at full aperture in Av priority mode.

But k1-00d and Eric seem to say that the K lens will be automatically stop down to selected shooting aperture when shutter is actuated.

Maybe I do not understand this properly... but there seems a divergence in views of how the K series lens will work on a K10/20D.

Once again, thanks so much for your insights.

Bharat
03-07-2008, 10:34 PM   #6
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Have a quick look at this site. They have a lot of goodies.

Vintage Visuals Photographic
03-07-2008, 11:09 PM   #7
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Basically, if you use the M/K version in Av mode, it won't stop down for you. If you have it in M mode, it will.

For totally manual lens, I simply focus at wide open, then stop down, meter it and shoot. You do need to pick the main point to focus on so that later stop down would only extend from that point.


QuoteOriginally posted by Khukri Quote
Dear k100d, Eric and Lowell,

Thank you so much for your inputs; I do appreciate the time you took to write this, Lowell!

So, if you happen to come across a spare 85mm/1.8 (after you have got one for yourelf!), Lowell, do give me a holler! My email is <khukri@hotmail.com>

I generally do not use normal 50mm optics, except occasionally the 50 macro. I am into either very wide (<28mm) or very telephoto (>200mm) landscapes/nature.

I also note that all of you are from Canada. And I am looking for Pentax stuff from Canada to be purchased within the next month. Incase you or any of your friends or retai outlest syou know are disposing accessories that can be used on a K20D let me know. Stuff like angle finder, viewfinder magnifier and yes, a 50mm/2.8 macro.

Before I end may I wish a slight clarification, please:

Lowell, you say that, "K mount lenses - .... in Av mode the lens will remain wide open and shot taken at maximum apature but metered for it."

k100d, you say that, "no, the lens will stop down when the shutter is pressed"

And Eric, says, "Yes, with M and K lenses the camera will automatically stop the lens down when the shutter is pressed."

From above quote of Lowell, I understand that the K lens will work only at full aperture in Av priority mode.

But k1-00d and Eric seem to say that the K lens will be automatically stop down to selected shooting aperture when shutter is actuated.

Maybe I do not understand this properly... but there seems a divergence in views of how the K series lens will work on a K10/20D.

Once again, thanks so much for your insights.

Bharat
03-08-2008, 06:25 AM   #8
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QuoteOriginally posted by Khukri Quote
Dear k100d, Eric and Lowell,

Thank you so much for your inputs; I do appreciate the time you took to write this, Lowell!

So, if you happen to come across a spare 85mm/1.8 (after you have got one for yourelf!), Lowell, do give me a holler! My email is <khukri@hotmail.com>

I generally do not use normal 50mm optics, except occasionally the 50 macro. I am into either very wide (<28mm) or very telephoto (>200mm) landscapes/nature.

I also note that all of you are from Canada. And I am looking for Pentax stuff from Canada to be purchased within the next month. Incase you or any of your friends or retai outlest syou know are disposing accessories that can be used on a K20D let me know. Stuff like angle finder, viewfinder magnifier and yes, a 50mm/2.8 macro.

Before I end may I wish a slight clarification, please:

Lowell, you say that, "K mount lenses - .... in Av mode the lens will remain wide open and shot taken at maximum apature but metered for it."

k100d, you say that, "no, the lens will stop down when the shutter is pressed"

And Eric, says, "Yes, with M and K lenses the camera will automatically stop the lens down when the shutter is pressed."

From above quote of Lowell, I understand that the K lens will work only at full aperture in Av priority mode.

But k1-00d and Eric seem to say that the K lens will be automatically stop down to selected shooting aperture when shutter is actuated.

Maybe I do not understand this properly... but there seems a divergence in views of how the K series lens will work on a K10/20D.

Once again, thanks so much for your insights.

Bharat
Ageispan has responded correctly.

For the lens to stop down you must be in manual mode. Av mode only meters and shoots with the lens wide open.

If you have an M42 mount, it must be set to manual apatue and then when using the K mount adaptor, as you select apature the lens stops down at that point, therefore Av mode works with M42 lenses, but the viewfinder darkens as the lens stops down

03-08-2008, 06:41 AM   #9
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Hi Bharat, I won't go over what others have said as their information is correct. I don't own any of the manual lenses you speak of except the SMC 135 F2.5, I've found that that lens meters quite well with the K10D, in very bright light it underexposes by about 1/3 of a stop when mostly open, but other than that I've had no problems with it, and to be frank, it is rare that I use a wide aperture in bright light. BTW the 135 F2.5 is a magnificent lens.

NaCl(hope that helps)H2O
03-08-2008, 07:14 AM   #10
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QuoteOriginally posted by NaClH2O Quote
Hi Bharat, I won't go over what others have said as their information is correct. I don't own any of the manual lenses you speak of except the SMC 135 F2.5, I've found that that lens meters quite well with the K10D, in very bright light it underexposes by about 1/3 of a stop when mostly open, but other than that I've had no problems with it, and to be frank, it is rare that I use a wide aperture in bright light. BTW the 135 F2.5 is a magnificent lens.

NaCl(hope that helps)H2O
Salty

couldn't agree more about the 135F2.5, very nice lens, picked one up about 6 months ago
03-11-2008, 05:25 AM   #11
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Thank you one and all for additional clarifications. I now have understood how the aperture will work in Av/M modes.

Now to look for such lenses as the 135/2.5 and the 200/2.5...!

Any idea how efficient AF will be and also how good the image quality will be if a 200/2.5 is attached to a 1.7x TC for close up photography? Or will a 100 macro + 1.7x TC offer better results?

Bharat
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